GitOps 应用实践系列 - Argo CD 上手实践

张晋涛 - 2021-11-01 08:16:40

大家好，我是张晋涛。

在前两篇内容中，我分别为大家介绍了 GitOps 的概念，以及用于实施 GitOps 的工具 Argo CD。本篇我们将以一个示例项目为大家介绍 Argo CD 的实践。

创建集群

我们通过 KIND（Kubernetes in Docker）工具创建一个用于本地测试的 Kubernetes 集群。使用如下的配置文件，创建一个包含一个 control plane 和三个 work 的集群。

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
- role: worker
- role: worker
- role: worker

使用如下命令进行集群的创建：

➜ (MoeLove) kind create cluster --config=kind-config.yaml 
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.20.2) ? 
 ✓ Preparing nodes ? ? ? ?  
 ✓ Writing configuration ? 
 ✓ Starting control-plane ?️ 
 ✓ Installing CNI ? 
 ✓ Installing StorageClass ? 
 ✓ Joining worker nodes ? 
Set kubectl context to "kind-kind"
You can now use your cluster with:

kubectl cluster-info --context kind-kind

Have a nice day! ?

执行如下命令等待集群完全 Ready：

➜ (MoeLove) kubectl wait --for=condition=Ready nodes --all

部署 Argo CD

待集群状态完全 Ready 后，开始进行 Argo CD 的部署。我们创建一个名为 argocd 的 namespace。

部署

这里可以直接使用 Argo CD 项目中提供的部署文件进行安装。这里需要注意的是 此部署文件中 RBA 的配置中引用了 argocd 这个 namespace，所以如果你是将它部署到其他 namespace 中，那一定要进行对应的修改。

➜ (MoeLove) kubectl create ns argocd
namespace/argocd created
➜ (MoeLove) kubectl -n argocd apply -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
customresourcedefinition.apiextensions.k8s.io/applications.argoproj.io created
customresourcedefinition.apiextensions.k8s.io/appprojects.argoproj.io created
serviceaccount/argocd-application-controller created
serviceaccount/argocd-dex-server created
serviceaccount/argocd-redis created
serviceaccount/argocd-server created
role.rbac.authorization.k8s.io/argocd-application-controller created
role.rbac.authorization.k8s.io/argocd-dex-server created
role.rbac.authorization.k8s.io/argocd-server created
clusterrole.rbac.authorization.k8s.io/argocd-application-controller created
clusterrole.rbac.authorization.k8s.io/argocd-server created
rolebinding.rbac.authorization.k8s.io/argocd-application-controller created
rolebinding.rbac.authorization.k8s.io/argocd-dex-server created
rolebinding.rbac.authorization.k8s.io/argocd-redis created
rolebinding.rbac.authorization.k8s.io/argocd-server created
clusterrolebinding.rbac.authorization.k8s.io/argocd-application-controller created
clusterrolebinding.rbac.authorization.k8s.io/argocd-server created
configmap/argocd-cm created
configmap/argocd-cmd-params-cm created
configmap/argocd-gpg-keys-cm created
configmap/argocd-rbac-cm created
configmap/argocd-ssh-known-hosts-cm created
configmap/argocd-tls-certs-cm created
secret/argocd-secret created
service/argocd-dex-server created
service/argocd-metrics created
service/argocd-redis created
service/argocd-repo-server created
service/argocd-server created
service/argocd-server-metrics created
deployment.apps/argocd-dex-server created
deployment.apps/argocd-redis created
deployment.apps/argocd-repo-server created
deployment.apps/argocd-server created
statefulset.apps/argocd-application-controller created
networkpolicy.networking.k8s.io/argocd-application-controller-network-policy created
networkpolicy.networking.k8s.io/argocd-dex-server-network-policy created
networkpolicy.networking.k8s.io/argocd-redis-network-policy created
networkpolicy.networking.k8s.io/argocd-repo-server-network-policy created
networkpolicy.networking.k8s.io/argocd-server-network-policy created

查看状态

➜ (MoeLove) kubectl -n argocd get deploy
NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
argocd-dex-server    0/1     1            1           1m
argocd-redis         0/1     1            1           1m
argocd-repo-server   1/1     1            1           1m
argocd-server        0/1     1            1           1m

获取密码：

默认情况下安装好的 Argo CD 会启用基于 Basic Auth的身份校验，我们可以在 Secret 资源中找到对应的密码。但需要注意的是 这个名字为argocd-initial-admin-secret的 sercret 资源是等到 Pod 处于 Running 状态后才会写入。

# 等待 Pod 全 Ready
➜ (MoeLove) kubectl wait --for=condition=Ready pods --all -n argocd
pod/argocd-application-controller-0 condition met
pod/argocd-dex-server-5fc596bcdd-lnx65 condition met
pod/argocd-redis-5b6967fdfc-mfbrr condition met
pod/argocd-repo-server-98598b6c7-7pmgb condition met
pod/argocd-server-5b4b7b868b-bjmzz condition met

# 获取密码
➜ (MoeLove) kubectl  -n argocd get secret argocd-initial-admin-secret -o template="{{ .data.password | base64decode }}" 
AFbmuBSmRo1F0Dow

通过 UI 访问它

我们可以通过 kubectl port-forward 将 argocd-server 的 443 端口映射到本地的 9080 端口。

➜ (MoeLove) ➜ (MoeLove) kubectl port-forward --address 0.0.0.0 service/argocd-server -n argocd 9080:443

这样在浏览器中就可以 ArgoCD dashboard ，这是 username 是 admin, 以及 password 便可以前面提到的『获取密码』章节。

命令行访问：

如果你不喜欢通过浏览器进行操作，那也可以使用 Argo CD 提供的 CLI 工具。

➜ (MoeLove) wget https://github.com/argoproj/argo-cd/releases/download/v2.1.2/argocd-linux-amd64 -O argocd
➜ (MoeLove) chmod +x argocd
➜ (MoeLove) mv argocd /bin/argocd

# 执行这条命令前，我们先通过 kubectl port-forward 进行了端口转发
➜ (MoeLove) argocd login localhost:9080
WARNING: server certificate had error: x509: certificate signed by unknown authority. Proceed insecurely (y/n)? y
Username: admin
Password: 
'admin:login' logged in successfully
Context 'localhost:9080' updated

部署应用

这里我创建了一个示例项目，完整内容可以在我的 GitHub https://github.com/tao1234566... 获取到。

创建目标 namespace

➜ (MoeLove) kubectl  create ns kustomize
namespace/kustomize created

创建 app

这里可以选择在 Argo CD 的 UI 中直接配置，也可以使用 Argo CD 的 CLI 来配置，这里我以 CLI 配置为例

➜ (MoeLove) argocd app create argo-cd-demo --repo https://github.com/tao12345666333/argo-cd-demo.git --revision kustomize --path ./kustomization --dest-server https://kubernetes.default.svc --dest-namespace kustomize 
application 'argo-cd-demo' created

其中：

--repo 指定部署应用所使用的仓库地址；--revision 指定部署应用所使用的分支，这里我使用了一个名为 kustomize 的分支；--path 部署应用程序用到的 manifest 所在的位置--dest-server 目标 Kubernetes 集群的地址--dest-`namespace` 应用要部署的目标 namespace查看状态

当 Application 创建完成后，也可以直接在 UI 上看到具体信息：

或者通过 argocd 在终端下进行查看：

➜ (MoeLove) argocd app get argo-cd-demo
Name:               argo-cd-demo
Project:            default
Server:             https://kubernetes.default.svc
Namespace:          kustomize
URL:                https://localhost:8080/applications/argo-cd-demo
Repo:               https://github.com/tao12345666333/argo-cd-demo.git
Target:             kustomize
Path:               ./kustomization
SyncWindow:         Sync Allowed
Sync Policy:        <none>
Sync Status:        OutOfSync from kustomize (e8a2d77)
Health Status:      Missing

GROUP  KIND        NAMESPACE  NAME          STATUS     HEALTH   HOOK  MESSAGE
       Service     kustomize  argo-cd-demo  OutOfSync  Missing        
apps   Deployment  kustomize  argo-cd-demo  OutOfSync  Missing

可以看到当前的 Application 状态是 OutOfSync ，所以我们可以为它触发一次 sync 操作，进行首次部署。

sync

可以在 UI 上点击 SYNC 按钮，或者通过 argocd CLI 来触发同步操作。

➜ (MoeLove) argocd app sync argo-cd-demo
TIMESTAMP                  GROUP        KIND   NAMESPACE                  NAME    STATUS    HEALTH        HOOK  MESSAGE
2021-10-30T10:35:33+00:00            Service   kustomize          argo-cd-demo  OutOfSync  Missing              
2021-10-30T10:35:33+00:00   apps  Deployment   kustomize          argo-cd-demo  OutOfSync  Missing              
2021-10-30T10:35:35+00:00            Service   kustomize          argo-cd-demo    Synced  Healthy              
2021-10-30T10:35:35+00:00            Service   kustomize          argo-cd-demo    Synced   Healthy              service/argo-cd-demo created
2021-10-30T10:35:35+00:00   apps  Deployment   kustomize          argo-cd-demo  OutOfSync  Missing              deployment.apps/argo-cd-demo created
2021-10-30T10:35:35+00:00   apps  Deployment   kustomize          argo-cd-demo    Synced  Progressing              deployment.apps/argo-cd-demo created

Name:               argo-cd-demo
Project:            default
Server:             https://kubernetes.default.svc
Namespace:          kustomize
URL:                https://localhost:8080/applications/argo-cd-demo
Repo:               https://github.com/tao12345666333/argo-cd-demo.git
Target:             kustomize
Path:               ./kustomization
SyncWindow:         Sync Allowed
Sync Policy:        <none>
Sync Status:        Synced to kustomize (e8a2d77)
Health Status:      Progressing

Operation:          Sync
Sync Revision:      e8a2d77cf0e5405ba9e5dc70d3bf44da91b3ce00
Phase:              Succeeded
Start:              2021-10-30 10:35:33 +0000 UTC
Finished:           2021-10-30 10:35:35 +0000 UTC
Duration:           2s
Message:            successfully synced (all tasks run)

GROUP  KIND        NAMESPACE  NAME          STATUS  HEALTH       HOOK  MESSAGE
       Service     kustomize  argo-cd-demo  Synced  Healthy            service/argo-cd-demo created
apps   Deployment  kustomize  argo-cd-demo  Synced  Progressing        deployment.apps/argo-cd-demo created

同步成功后，在 UI 上也能看到当前应用和同步的状态。

点击查看详情，可以看到应用部署的拓扑结构：

验证效果CI

接下来在 kustomize 分支，进行一些代码上的修改，并提交到 GitHub 上。此时会触发项目中基于 GitHub Action 的 CI，我们来看看其具体的配置：

  deploy:
    name: Deploy
    runs-on: ubuntu-latest
    continue-on-error: true
    needs: build

    steps:
      - name: Check out code
        uses: actions/checkout@v2

      - name: Setup Kustomize
        uses: imranismail/setup-kustomize@v1
        with:
          kustomize-version: "4.3.0"

      - name: Update Kubernetes resources
        env:
          DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
        run: |-
          cd manifests
          kustomize edit set image ghcr.io/${{ github.repository }}/argo-cd-demo:${{ github.sha }}
          cat kustomization.yaml
          kustomize build ./ > ../kustomization/manifests.yaml
          cat ../kustomization/manifests.yaml

      - uses: EndBug/add-and-commit@v7
        with:
          default_author: github_actions
          branch: kustomize

可以看到这里其实利用了 kustomize 这个工具，将最新的镜像写入到了部署应用所用的 manifest.yaml 文件中了，然后利用 EndBug/add-and-commit@v7 这个 action 将最新的 manifest.yaml 文件再提交回 GitHub 中。

查看状态

此时当 Sync 再次触发后，我们也就可以看到最新的部署拓扑了。